Sun Tunnel Installation and Replacement Cost Calculator

How this calculator works

This calculator estimates a realistic price range rather than a single figure, because real-world quotes genuinely vary that much. It starts from typical UK supplied-and-fitted price ranges drawn from published 2026 industry cost guides, then multiplies them by the number of units you enter and by adjustment factors for each choice you make below. The result is a low-to-high band that a fair quote is likely to fall within, not a promise of the exact price you will pay.

A sun tunnel typically costs around to supplied and fitted in 2026, with the kit itself commonly to and labour for a straightforward pitched roof installation a few hours’ work. That makes sun tunnels one of the cheapest ways to get natural daylight into internal rooms, at a fraction of the structural work a full roof window or skylight would need.

Number of sun tunnels

Enter how many sun tunnels you are pricing. They are typically fitted one per room, most often to windowless hallways, landings, bathrooms and walk-in wardrobes where a full roof window is impossible or unnecessary.

Tunnel type

Rigid tunnels use straight, highly reflective tubes and deliver noticeably more light, but they need a clear straight run from roof to ceiling. Flexible tunnels can bend around pipes, tanks and framing, and the kits are usually a little cheaper, but each bend and the ribbed surface costs light output. Where a straight run exists, rigid is almost always the better buy.

Tunnel diameter

Sun tunnels come in standard diameters of roughly 25 and 35 centimetres. The larger diameter delivers substantially more light for a modest extra cost and suits normal rooms, while the smaller size suits cupboards, small bathrooms and short tunnel runs.

Specification level

Two windows that look similar from the street can sit at very different price points. Budget products use simpler profiles, standard hardware and basic glass. Mid-range covers the typical A-rated units most UK installers quote by default. Premium covers high-end systems with upgraded security hardware, better thermal performance, special finishes or designer profiles, and typically adds around 30 percent to the price.

Where you live

Labour rates are not uniform across the UK. Published cost guides consistently show installation prices in London and the South East running roughly 20 to 30 percent above the national average, driven by higher labour costs, travel, parking and congestion charges. The calculator applies an uplift of around 20 percent if you select London and the South East. Product prices themselves are broadly similar nationwide, so the difference mostly reflects fitting costs.

What else affects the price

Sun tunnel pricing depends mainly on the tunnel length and route, the roof covering, and the flashing kit needed to weatherproof the roof end. Longer runs through deep lofts need extension tubes and lose some light along the way. The roof-side dome or flat collector must match your tile or slate profile, and the ceiling diffuser choice affects the look of the light in the room. Remember a sun tunnel provides daylight only, not ventilation or a view, and output on dark winter days is modest, so some households pair one with a built-in electric light for night use.

Planning permission, building regulations and certification

Most roof glazing falls under permitted development rights, provided the units do not project more than 150 millimetres above the roof plane and sit no higher than the highest part of the roof, but conservation areas, listed buildings and flats have tighter rules, so check with your local planning authority before ordering. Building regulations apply regardless of planning status, covering structural alterations, thermal performance, safety glazing and, in loft conversions, escape and ventilation requirements. Installers registered with a competent person scheme can self-certify that replacement glazing complies with the regulations and issue a certificate you will need when selling the property; for structural roof work, building control involvement is normally required.